21943681943 has 2 divisors, whose sum is σ = 21943681944. Its totient is φ = 21943681942.

The previous prime is 21943681933. The next prime is 21943681961. The reversal of 21943681943 is 34918634912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21943681943 - 2⁸ = 21943681687 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 21943681891 and 21943681900.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21943681933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10971840971 + 10971840972.

It is an arithmetic number, because the mean of its divisors is an integer number (10971840972).

Almost surely, 2^21943681943 is an apocalyptic number.

21943681943 is a deficient number, since it is larger than the sum of its proper divisors (1).

21943681943 is an equidigital number, since it uses as much as digits as its factorization.

21943681943 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1119744, while the sum is 50.

The spelling of 21943681943 in words is "twenty-one billion, nine hundred forty-three million, six hundred eighty-one thousand, nine hundred forty-three".